This included the argument that the trial judge, Justice Anthony Whealy, should have instructed the jury that manslaughter and infanticide were alternative charges to consider when deciding on their verdict.

Lane's defence team, which Mr Archbold said would be led by defence barrister Winston Terracini SC, will also argue that the Crown Prosecutor in the case, Mark Tedeschi, QC, reversed the onus of proof in his closing address by positing a series of questions that he said the defence had to answer.

In criminal trials the prosecution must prove a person's guilt, rather than the defence proving their innocence.

"She really does maintain her innocence. It's been a long fight and she's looking forward to her appeal and she's excited by it."

He said the defence team would also lodge an application for bail which they expected to be heard early next year.

"We believe that the grounds of appeal warrant her being on the outside. It's going to be a lengthy appeal ... a person shouldn't remain languishing in custody.

"There's been no baby found, there's been no cause of death – nothing can be ruled out."

The developments come after the trial's presiding judge, retired Supreme Court Justice Anthony Whealy, QC, revealed to Fairfax he did not personally believe the Crown had proved its case against Lane, and he was unconvinced of her guilt.

Lane, the trial heard, had multiple secret pregnancies in the 1990s, two ending in termination and two in adoption. Tegan was born at Auburn hospital on September 12, 1996, and within hours of her discharge two days later, Lane appeared at a friend's wedding without the infant. The child has not been seen since.

Among the points to be argued on the appeal is that the guilty verdict was unsafe, as it cannot be supported by the evidence.

In documents seen by Fairfax Media, it is submitted that the body of Tegan Lane – if she is dead – has never been discovered, or located, meaning that the Crown cannot point to any deliberate act done by Lane to cause her death.